Back again with more questions on the 241 Hemi that had a burned head gasket. I have a number of spare cylinder heads for the 241 and 270 engine. I was thinking of putting the 270 heads on the 241 block. Will I gain anything? The issues i hear about concern the geometry of the rockers with the valve stem, the valves clearing the cylinder walls, header gasket thickness, effect on compression, and I'm sure many of you know of other issues.

Another thing I'd like to figure out; can someone track down the casting numbers i found on the heads to determine whether they are 241 or 270? One set of heads had #1554132 2 and 1554132 3, the other heads were 1828362 3.
If anyone can help, that would be great.

I've been told on the last digit on the casting numbers is how many times that form, casting core? I can't think of the proper name for them now, was used on making that cast part I've seen some cast parts with -10 as the highest number on OEM Mopar stock castings.
As far as your heads can you do some measuring on the combustion chamber size ( outside diameter and CC) and the valve sizes as well as can you get a couple of light weight checking springs so you can set both sets of heads on your block to check and see if the valves hit the block or not when opening them by hand
I know nothing about the early Dodge hemi motors, I did run a 1955 New Yorker motor in my first hot rod and that got me into the early Chrysler Hemi motors and later into the 426 hemi motors
As far the change in which part Dodge did to make those motor bigger on the C.I. I would look up the stock bore and stroke sizes and go from their Think about LA motors with the 273, 318 and 340 having the same stroke and rod lengths same thing on the early Chrysler hemi, 331 and 354 C.I. same stroke, different bore sizes.
IHTHS

the 1554132 heads are 55 car and truck 270ci
the 1828362 heads are not in any info i have.
however, there is a 1328362 that is for 53-54 car and truck 241 applications.
possibly the 8 may be a 3 ?

That would be incorrect. It is the number of the mold that made the core, nothing more. It is used for QA purposes so that if there is an issue with the cores being made they know which mold made them. Otherwise they'd have to use one mold to make all the cores or inspect every mold if a defect in the cores is discovered.

Since Chrysler was doing volume production they weren't using one mold, like you would if it was just a prototype setup or similar. Inspecting every mold for core issues would be very costly and would shut down production completely till the offending mold was found.

Which is why the molds were numbered.

correct. the "- number" is the core mold box number used to identify the mold.

Thanks!
Can the 1554132 heads be used on the 241 block? Would there be a worthwhile gain in performance?

it may be possible, but i can't say for sure.
it looks like the intake valve size is the only difference ?
Hot Heads would be the guys to ask, i would think.
every time these early engines come up, it makes me think i need to build one of the 392's i have on the rack.
then reality sets in, and i realize my "shopping days are fast running out"................
so lately, i've been contemplating selling them, not because i have to, or they would be expensive to build, but because of health issues that require the funds to go there instead.
please keep us posted on this topic if you could.

Those motors were never real popular in drag racing or in street racing that I can remember due to their small C.I., I think asking about them on a street rudder forum may be more helpful than asking on here as far as real hands one personal experiences with those motors

maybe check over on the HAMB board ?